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The clinical value of therapeutic plasma exchange in multifocal motor neuropathy
Helmar C Lehmann1, Felix R Hoffmann, Andreas Fusshoeller
1Department of Neurology, Heinrich-Heine-University of Düsseldorf, Germany. helmar.lehmann@uni-duesseldorf.de
Objective:
Although there is evidence for a pathogenic role of humoral factors in multifocal motor neuropathy (MMN), plasma exchange (PE) is assumed to be an ineffective treatment. We set out to elucidate possible reasons for this apparent contradiction.
Methods:
A retrospective analysis of seven patients with MMN, who underwent 4 to 18 sessions of PE. Clinical response, electrophysiological parameter and anti-ganglioside antibody titers were reviewed.
Results:
Two patients, who had anti-ganglioside antibodies, exhibited transient clinical responses to PE, manifested by improved neurological function. Whereas electrophysiological parameters continued to worsen in all patients, anti-ganglioside antibody titers declined during PE, but increased after PE.
Conclusion:
PE is of limited therapeutic value in patients with MMN, who do not respond to established treatment options. It may only be useful as an adjunctive treatment in a subset of patients. The transient decrease of anti-ganglioside-antibodies titers suggests that pathogenic humoral factors in MMN are only temporarily reduced. Further, PE treatment alone is insufficient to prevent axons from continuing degeneration, which may explain the failure of PE to substantially influence the disease course of patients with MMN.
Insights
Plasma exchange (PE) offers limited benefit for multifocal motor neuropathy (MMN), despite transiently reducing anti-ganglioside antibodies. Continued axonal degeneration suggests PE alone is insufficient for substantial disease modification in MMN patients.
Area of Science:
- Neurology
- Immunology
- Neuron science
Background:
- Humoral factors are implicated in multifocal motor neuropathy (MMN) pathogenesis.
- Plasma exchange (PE) is generally considered ineffective for MMN treatment.
Purpose of the Study:
- To investigate reasons for the perceived ineffectiveness of PE in MMN.
- To evaluate the impact of PE on clinical response, electrophysiology, and antibody titers in MMN patients.
Main Methods:
- Retrospective analysis of seven MMN patients undergoing 4-18 PE sessions.
- Review of clinical outcomes, electrophysiological parameters, and anti-ganglioside antibody titers.
Main Results:
- Two patients with anti-ganglioside antibodies showed transient clinical improvement.
- Electrophysiological parameters worsened in all patients despite PE.
- Anti-ganglioside antibody titers decreased during PE but rebounded afterward.
Conclusions:
- PE has limited therapeutic value in MMN, potentially serving as an adjunctive therapy for a subset of patients.
- Transient reduction of pathogenic humoral factors suggests PE's temporary effect.
- PE alone cannot prevent axonal degeneration, explaining its limited impact on MMN progression.
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